Simplified TeV leptophilic dark matter in light of DAMPE data

Abstract

Using a simplified framework, we attempt to explain the recent DAMPE cosmic $e^{+}+e^{-}$ flux excess by leptophilic Dirac fermion dark matter (LDM). The scalar (${\Phi }_0$) and vector (${\Phi }_1$) mediator fields connecting LDM and Standard Model particles are discussed. Under constraints of DM relic density, gamma-rays, cosmic-rays and Cosmic Microwave Background (CMB), we find that the couplings $P\otimes S$, $P\otimes P$, $V\otimes A$ and $V\otimes V$ can produce the right bump in $e^{+}+e^{-}$ flux for a DM mass around 1.5 TeV with a natural thermal annihilation cross-section $<\sigma v>\sim 3\times 10^{-26}c{m}^3/s$ today. Among them, $V\otimes V$ coupling is tightly constrained by PandaX-II data (although LDM-nucleus scattering appears at one-loop level) and the surviving samples appear in the resonant region, $m_{{\Phi }_1}\simeq 2m_{\chi }$. We also study the related collider signatures, such as dilepton production $pp\to {\Phi }_1\to {\ell }^{+}{\ell }^{-}$, and muon $g-2$ anomaly. Finally, we present a possible $U(1{)}_X$ realization for such leptophilic dark matter.

Comments: discussions added, version accepted by JHEP